Procedure and device for radiochromatography

ABSTRACT

Radiochromatographic procedure for analysing of a substance having a gamma-radiating isotope added to it using a spark chamber with a cathode surface, a grid and an anode, a sample of said substance being laid on a chromatographic plate, placed on the cathode surface and used as electron emitting cathode, said electrons being composed of emitted beta-radiation from gamma decay and of Auger- and conversion electrons, the isotope atoms which are bound in the substance or possible free isotope atoms, which migrated from the substance, being detected by means of the spark chamber so as to establish the distribution and the concentration of the isotope atoms in the substance.

United States Patent 1191 Asard i [451 Apr. 9, 1974 PROCEDURE AND DEVICE FOR RADIOCHROMATOGRAPHY Inventor:

Assignee:

Filed:

US. Cl ..250/303, 250/375, 250/393 Int. Cl. H0lj 3/22 Field of Search 250/71, 71.5 S, 83.3 R,

References Cited UNITED STATES PATENTS Primary Examiner-James W. Lawrence Assistant Examiner-D. Nelms Attorney, Agent, or FirmLarson, Taylor & Hind [5 7] ABSTRACT Radiochromatographic procedure for analysing of a substance having a gamma-radiating isotope added to it using a spark chamber with a cathode surface, a grid and an anode, a sample of said substance being laid on a chromatographic plate, placed on the cathode surface and used as electron emitting cathode, said electrons being composed of emitted beta-radiation from gamma decay and of Augerand conversion electrons, the isotope atoms which are bound in the substance or possible free isotope atoms, which migrated from the substance, being detected by means of the spark chamber so as to establish the distribution and the concentration of the isotope atoms in the substance.

6 Claims, 2 Drawing Figures PROCEDURE AND DEVICE FOR RADIOCIIROMATOGRAPI-IY The invention relates to a procedure in radiochromatography for use of a substance to which a gamma-radiating isotope is added and to a device for putting the procedure into practice.

For measurements of the above-mentioned kind medicine makes use among other things of a spark chamber, which is a chamber containing a cathode, a grid and an anode for the detection of radiation coming from a substance prepared with radioactive matter and injected in an organ of a patients body. For reasons of radiations range of action one is compelled to employ gamma-radiating compounds by which for example tumors and other body illnesses can be revealed and located.

When detecting gamma rays a spark chamber can be used consisting of a cathode covered with a conversion layer, which transfers gamma radiation to the electrons, as well as of a grid and an anode. The cathode should be irradiated by a parallel beam, while the parallelism is obtained in a collimator which consists of a relatively thick lead plate provided with a large number of holes placed in parallel. The grid and the anode are herewith placed at such distance from each other'and are kept with such potentials, that the electrodes function to the point of spark discharge. When the cathode is irradiated with gamma rays, photoand Comptonelectrons are emitted and cause spark discharges between the grid and the anode. The position of the sparks at the anode gives therefore a picture of the state of the examined organ and if the anode is exposed for a longer time in front of a photo-camera, a picture is obtained on the film, with the aid of which the state of the examined organ can be analysed.

It can, however, happen that the compound, which is injected in the organs to be examined, does not always possess the desired, qualities. For this reason the demand arose to control in advance to what extent the atoms of the gamma-radiating compound fastens for example to colloid, which constitutes the substance to be injected and accumulated in some of. the patients organs, in this case the liver. This control has up to now been exercised so that a sample of the prepared colloid is applied on a chromatographic plate, whereupon an X-ray film is placed on the chromatographic plate and the film exposed. The exposure time is as in the previous case very long, usually up to half a day. This results in a great delay in connection with the taking of tests, before the injection and the following analytical examination of the patient can take place. This is a great inconvenience, especially as it is desirable to work with isotopes, which have a short half-life, so that the ray-dose to the patient should be as small as possible. Therefore, it is often desirable to work with isotopes which have a half-life not over 2 hours, and it is then nearly impossible to carry out with conventional methods a control of the prepared substance, if this check takes several hours.

The present invention is intended to eliminate these disadvantages and bring about a procedure which enables the laboratory tests of the substances, intended for injection, to be carried out quickly and reliably. The invention relates thus to a procedure in radiochromatography for using a substance with an admixture of a gamma-radiating isotope, use of a spark chamber, containing a cathode surface, a grid and an anode, and is characterized mainly in that a sample of the substance with a gamma-radiating isotope preferably is first placed on a chromatographic plate and placed on the cathode surface, to be used as an electron emitting cathode, where the emitted electrons consist of betaradiation emitted at gamma decay and of Augerand conversion electrons, while the isotopes bound in the substance and possibly free ones, migrated from the substance, are detected by the spark chamber in order to determine the distribution and concentration of isotope atoms in the substance. It is advisable therefore to connect the chromatographic plate and the cathode surface electrically. In order to enable a detailed analysis of the sample it is advisable to take a photographic exposure of the configurations presented by the spark chamber.

The invention embraces also a device to carry out the procedure as mentioned above. The device consists of a spark chamber with a cathode surface, a grid, in the main parallel to it, and an anode'placed at some distance therefrom. The device is characterized chiefly in that the cathode surface is arranged to take up the substance which is prepared with a gamma-radiating isotope and placed on a chromatographic plate, while the electrons in the spark chamber are mainly composed of beta-rays emitted at gammas decay and of Augerand conversion electrons.

According to a suitable embodiment of the invention the grid and the anode are placed at such distance from each other and connected to such potentials, that the named electrodes are at the point of spark discharge. Each electron emitted at gamma decay causes a spark in the spark chamber, which in turn gives a lightspot on the photofilm.

The procedure and the device enable according to the invention a fast and effective control in a laboratory of, for example, an injection of substances in some of the patients organs, whereby a picture can be'obtained' within the space of a few minutes for analysis, whilst up to now, all known procedures have required at least 10 hours.

With reference to the attached drawings the embodiment of the invention for the practice of the procedure according to the invention will be described. The following figures show:

FIG. 1 a known conventional device for the detection of gamma radiation, emanating from a substance injected in some of the patients organs, and

FIG. 2 a device according to the invention for control of the qualities of a substance designed for injection.

On FIG. 1 a known device for the detection of gamma-rays is shown, coming for example from a compound injected in one of patients organs. The device includes a spark chamber 1, containing a cathode 2, covered with a conversion layer, a grid 3 and an anode 4, whereby the grid and the anode over a resistance R are kept at such potentials, that depending of the reciprocal distance between the grid and the anode, they work at the point of spark discharge. In an organ 6 in a patients body a substance has been injected, which was prepared with a gamma-radiating isotope. The divergent beam-ray 7 passes a collimator 5 consisting of a lead plate with a great number of parallel holes 5a. The rays 8 coming out of the collimator 5 are parallel and the gamma-rays meet the cathode 2 at a right angle. The gamma-rays are transformed to an electron flow whereby each and everyone of the electrons causes a spark between the grid 3 and the anode 4. On the latter appears consequently a picture of isotope atoms distribution in the substance, which is accumulated in the organ 6. These sparks appear successively under a longer period of time and by means of camera 10, which stands with an open shutter, the spark picture 9 is being photographed, so that a diagnosis can be made with the help of the picture.

As the reliability of this method is to a high degree dependent on the substance injected having a suitable mixture and intended qualities, it is of great importance, that it can be carefully checked before the injection, which according to the invention has to be made in the device shown on FIG. 2. The above described device contains, according to the invention, a spark chamber 1, showing a cathode surface 2', a grid 3 running mostly parallel with this surface, and an anode 4 at a certain distance from this grid. Also this spark chamber has the grid 3 and anode 4 at such a distance from each other and has such potentials, that the point for spark discharge is nearly reached. Knowing that a gamma decay occurs in sending beta-rays as well as Augerand conversion electrons, the collimator according to the invention shown on FIG. 1, could be eliminated, as well as the conversion layer on the cathode. For the purpose of control a sample of the substance designed for injection is applied on the chromatographic plate, which is placed directly on the cathode surface 2'. Thereby the active isotope in the substance serves as a cathode, i.e., the emitted electrons come from the beta radiation in connection with gamma radiation, as well as from Auger and conversion electron radiation. These electrons cause sparks in the spark chamber 1, which are reproduced on the anode 4, and this reproduction can be photographed by a camera 10. This course of events takes place at a very high speed, the order of magnitude being between a few seconds and 1 minute. An effective method to control the substances designed for injections has hereby been obtained.

As the isotopes with a short half-life are being used more and more, there is therefore an increasing need to have the substances checked immediately before they are injected into a patients organ. The control can therefore no longer be made as before only by the manufacturers of the substances, but must also be moved, for example, to the hospitals. The simplified apparatus which is used following the procedure, according to the invention, results in that the control can now easily be done in every hospital immediately prior to the injection. This control can furthermore contrary to the conventional, more complicated method be reliably made by non-qualified personnel. The test results are 'quickly obtainable and the picture obtained gives a guide to a reliable analysis of the sample. The procedure as per invention is not limited to control of substances designed to be injected in some of a patients organs, but can naturally be applied for radiochromatography with gammaradiating isotopes.

What is claimed is:

1. In a radiochromatography process utilizing a sub stance to which a gamma-radiating isotope has been added, and using a spark chamber including a cathode surface, a grid and an anode, the improvement wherein a sample of the substance to which the gama-radiating isotope has been added is located on a chromatographic plate placed on the cathode surface of the spark chamber and is used as an electron-emitting cathode, the electrons emitted thereby comprising emitted beta-radiation from the gamma decay and Augerand conversion electrons; the isotope atoms being detected by means of the spark chamber so as to establish the distribution and concentration of the isotope atoms in the substance.

2. A process as claimed in claim 1 wherein the chromatographic plate is electrically connected to the cathode surface of the spark chamber.

3. A process as claimed in claim 1 further comprising photographing the distribution pattern of the isotope atoms as detected by the spark chamber inside and outside the substance.

4. A radiochromatographic apparatus for determining the concentration and a distribution of isotope atoms within a substance to which a gamma-radiating isotope has been added comprising a spark chamber including a grid, a cathode surface extending substantially parallel to said grid, and an anode spaced from said grid and said cathode surface, a chromatographic plate placed on the cathode surface, and a sample of a substance to which a gamma-radiating isotope has been added located on said chromatographic plate and serving as an electron emitting cathode, the electrons emitted thereby, and appearing in the spark chamber, comprising emitted beta-radiation from gamma decayand Augerand conversion electrons, said spark chamber detecting the isotope atoms so as to establish the concentration'and distribution of the isotope atoms in the substance.

5. An apparatus as claimed in claim '4 wherein saidber. 

1. In a radiochromatography process utilizing a substance to which a gamma-radiating isotope has been added, and using a spark chamber including a cathode surface, a grid and an anode, the improvement wherein a sample of the substance to which the gamaradiating isotope has been added is located on a chromatographic plate placed on the cathode surface of the spark chamber and is used as an electron-emitting cathode, the electrons emitted thereby comprising emitted beta-radiation from the gamma decay and Auger- and conversion electrons; the isotope atoms being detected by means of the spark chamber so as to establish the distribution and concentration of the isotope atoms in the substance.
 2. A process as claimed in claim 1 wherein the chromatographic plate is electrically connected to the cathode suRface of the spark chamber.
 3. A process as claimed in claim 1 further comprising photographing the distribution pattern of the isotope atoms as detected by the spark chamber inside and outside the substance.
 4. A radiochromatographic apparatus for determining the concentration and a distribution of isotope atoms within a substance to which a gamma-radiating isotope has been added comprising a spark chamber including a grid, a cathode surface extending substantially parallel to said grid, and an anode spaced from said grid and said cathode surface, a chromatographic plate placed on the cathode surface, and a sample of a substance to which a gamma-radiating isotope has been added located on said chromatographic plate and serving as an electron emitting cathode, the electrons emitted thereby, and appearing in the spark chamber, comprising emitted beta-radiation from gamma decay and Auger- and conversion electrons, said spark chamber detecting the isotope atoms so as to establish the concentration and distribution of the isotope atoms in the substance.
 5. An apparatus as claimed in claim 4 wherein said grid and said anode are spaced a predetermined distance apart, said apparatus further comprising means for applying potentials to said grid and said anode close to that required for spark discharge.
 6. An apparatus as claimed in claim 4 further comprising means for photographing the distribution pattern of isotope atoms as detected by the spark chamber. 